1. Field of the Invention
The invention relates to a fan control system and a fan controlling method thereof, and more particularly relates to a fan control system and a fan controlling method thereof to prevent a fan to continuously vibrate under a fixed frequency.
2. Description of the Related Art
Along with the advancement of technology, current electronic products are more and more slim and light. On the other hand, when an electronic apparatus operates, certain heat will generate. Without proper heat dissipation system, the electronic apparatus might be damaged due to temperature arising. Conventional heat dissipation system mainly utilizes a fan of rotational vane to perform heat dissipation, but such fan may not be suitable for a slim and light electronic product due to axial structure of the fan. Therefore, a smaller air pump fan device has been developed in the prior art.
An air pump fan device may be classified as piezoelectric fan made of piezoelectric material or an electromagnetic fan made of magnet and coils based on magnetic field operation. Taking piezoelectric fan as an example, a voltage is applied to a piezoelectric material to change shape of the piezoelectric material to further bring a thin plate connected to the piezoelectric material to vibrate. Therefore, the simple harmonic motion of the thin plate cause wind flow to achieve cooling effect. The air pump fan device has smaller size to save capacity for containing. In addition, the air pump fan device consumes less power and saves more energy.
However, it is unlike conventional fans with vanes, the air pump fan device in the prior art needs to be controlled to vibrate under an optimum resonance frequency. Under such resonance frequency, the vane has maximum amplitude for generating larger wind. But, when it is continuously vibrated under the same resonance frequency, there will be a single tone noise with narrow frequency and makes a user feel uncomfortable.
Therefore, it is necessary to design a new fan control system and fan controlling method thereof to solve conventional deficiency.